Process for making silk feltable.



: STATES PATENT GOTTFRTED DIESSER, OF ZURICH, SWITZERLAND.

PROCESS FOR MAKING SILK FELTABLE.

No Drawing.

To all whom it'may concern:

Be it known that I, GOTTFRIED DmssnR, a

' subject of the Emperor of Germany, residing at Zurich, Switzerland, have invented new and useful Improvements in Processes for Making Silk Feltable; and I do hereby declare the following to be a full, clear, and

exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The manufacture of felt is based on the property of certain fibrous materials to felt, that is to entangle in such a close manner under certain conditions that a compact body of great toughness is produced.

The process according to this invention depends on the albuminous character of the silk and on the absorbent properties of the latter and also on the property of the silk to partly dissolve in cold formic acid, with out a further cleaving of the molecule of fibroin taking place.

According to one convenient mode of carrying this invention into effect the short fibrous silk (waste-silk) is freed in a well known manner from the bast and then treated with cold water until the fiber is well washed. -Hereupon the silk is washed with formic acid until a fibrous pulp of uniform quality is obtained and this pulp is then put in suitable sieves, so that the formic acid can run ofl. The fibrous cake is then finally dried. Thus a.very tough body is obtained, which has at first a-paperlike appearance and which after having been treated in suitable machine's may then be converted into a felt-like body.

Specification of Letters Patent.

' Patented Oct. 19, 1915.

Application filed May 20, '1914. Serial No. 839,864.

According to a second convenient mode of carrying this invention into efi'ect the silk is at first freed in a well known manner from the bast and the material is then well Washed out and treated in water until a fibrous pulp of uniform quality is obtained.

Suitable provisions are then made for removing the excess of water and the pul action of gaseous formic acid.

In both cases the silk fiber is superficially dissolved by the formic acid, the degree of the solution depending upon the time during which said acid acts u on the fiber. During the volatilization 'o the formic acidthe P cake'is hereupon dried and exposed to the In testimony that I claimthe foregoing as my invention I have signed my name in presence of two subscrlbmg wltnesses.

GOTTFRIED DIESSER.

Witnesses CARL Snnwnn,

ARNOLD Lnnunn. 

